Spriter has this feature as an "experimental" demo.
To try it out, set "Drag new item" (PALETTE window) to "skins". Then dragging a sprite would turn it into a deformable mesh.
Unfortunately if you try to use a spriter file with a skin object in it, in c2's spriter runtime, it will fail to load your spriter file!
Brashmonkey has stated that this is not a feature they are planning to support with it's current implementation, and it is something to look forward to in spriter 2.
Until then, if you would like to have this feature, take a look at Kestrelmoon creature or Spine - both of which have the feature and a working runtime that supports it for construct2.plugin-spine-plugin_t90670kestrel-moon-creature-animation-software-runtime_t165653